The effectiveness of domestic water treatment processes, North West Province, South Africa

MSc (Environmental Sciences), North-West University, Mafikeng CampusPeople are increasingly concerned with the quality of water they drink. Globally, there is still an alarming rate of people who do not have access to basic services such as a supply of clean drinking water from the faucets. This is greatly concerning because our natural water reserves are diminishing exponentially as a result of climate change. Additionally, our water sources are increasingly polluted by anthropogenic activities; which makes the minority of people who are dependent on direct water source consumption at a higher health risk. In the Republic of South Africa, municipalities and independent water boards treat and supply domestic water to urban, semi-urban and some rural areas. This water is mainly for drinking purposes, hence it must meet the specified drinking water quality guidelines according to the South African National Standards (SANS 241) in order to be deemed safe for domestic use. The North West province, in general, is under-resourced, and made of under-privileged communities. Most municipalities in the North West are battling to maintain the aging water infrastructures. Hence, there is a challenge with the water quality, and supply, in places like Mmabatho. In this study, all parameters are measured and compared to specified drinking water quality limits according to the World Health Organisation (WHO) and the Department of Water Affairs; and then discussed with reference to the national drinking water standards (SANS 241). Current improvements of analytical methods allow for the detection of impurities, even at lower concentrations, and make it easier to ascertain the quality of the water. This study occurred at the water treatment plants of Mmabatho and Klerksdorp. The plant operators from Mmabatho Water Treatment Plant and Midvaal Water Company assisted with the collection of water samples from designated water sampling points; (i) before the treatment process (inlet), and (ii) after the treatment process (outlet). Sterilised and treated water sampling containers that were already labelled accordingly, were used to collect water for microbiological analysis. Sampling containers for chemical analysis were prewashed and oven dried prior to use. Physical parameters were measured in situ using various hand-held instruments; while the chemical and microbiological parameters were analysed ex situ using various laboratory instruments. Data processing, calculations and statistical analysis of all water quality variables was performed on results using one-way analysis of variance (ANOVA) at 0.05% level of significance with the objective of evaluating the significant differences among the two study areas as well as the seasonal variations. At the Midvaal Water Company, in Klerksdorp; the mean values of pH, temperature, electrical conductivity (EC), turbidity, total dissolved solids (TDS) and total suspended solids (TSS) before treatment were 8.86, 20.79 °C, 72.00 mS/cm, 21.09 NTU, 451.00 mg/L and 49.40 mg/L. After treatment, the mean values were 7.96, 23.80 °C, 73.75 mS/cm, 0.46 NTU, 482.00 mg/L and 35.75 mg/L. At the Mmabatho Water Treatment Plant, in Mmabatho; the mean values of the physical parameters: pH, temperature, EC, turbidity, TDS and TSS before treatment were 8.64, 20.88 °C, 222.25 mS/cm, 23.39 NTU, 428.39 mg/L and 284.27 mg/L. After treatment, the mean values were 8.81, 21.34 °C, 193.25 mS/cm, 6.01 NTU, 240.51 mg/L and 151.32 mg/L. All physical parameters from Klerksdorp were within specifications. The physical parameters in Mmabatho were within specifications, except for electrical conductivity and turbidity. The concentration of major ions nitrate, sulphate, chloride, sodium, magnesium and calcium before treatment in Klerksdorp were 1.51, 129.48, 50.44, 58.85, 21.22 and 58.51 mg/L. After treatment, the mean concentration were 1.77, 163.42, 54.79, 58.10, 23.87 and 63.69 mg/L. In Mmabatho, the concentration of these major ions before treatment were 2.66, 150.13, 222.35, 130.38, 26.72 and 172.60 mg/L. After treatment, ions concentration in Mmabatho were 1.22, 185.51, 226.29, 126.98, 22.67 and 155.67 mg/L. All major ions after treatment were well within specifications at both study areas, except for high levels of calcium concentration in Mmabatho. The concentration of free chlorine before treatment in Klerksdorp and Mmabatho was 0.00 mg/L. After treatment, the concentration of free chlorine was 1.49 and 3.87 mg/L in Klerksdorp and Mmabatho, respectively. These values fall within specified concentration for free chlorine after treatment. The mean concentration for total hardness for Klerksdorp and Mmabatho before treatment was 228.71 and 356.94 mg/L, respectively. After treatment, the total hardness was 55.19 and 264.79 mg/L, respectively. The hardness concentration was high at both sites before treatment, however, only in Klerksdorp this concentration fell within specifications after treatment. In Mmabatho, the total hardness concentration remained high. The mean values for Escherichia coli (E. coli) in Klerksdorp and Mmabatho before treatment were 29.75 and 33.50 CFU/100 mL, respectively. The total coliform detected at both sites before treatment was 38883.90 and 51190.25 CFU/100 mL, respectively. After treatment, both E. coli and total coliform were not detected at both study sites. The overall results for both the study sites after the water treatment process were comparable with the specified domestic water quality standards according to the SANS 241, except for the turbidity, electrical conductivity, total hardness and calcium at the Mmabatho Water Treatment Plant. This suggests that there is more work that needs to be done to investigate and safeguard the water sources in the North West province. This, in turn, will make it easier to mitigate and improve the water treatment processes in Mmabatho.Master